Optical pyrometer.



A. G. BURLEIGH.

OPTICAL PYROMETER.

APPLICATION FILED SEPT.3,1914.

Patented Dec. 1, 1914.

wh m Wm m m A f ur MB A my ARTHUR CILLE'Y nnntnmmor SEWIGKLEY, rnmvsnvamn,

oP'rIcA'L IQYROMETER.

To all whom it may concern Be it known that I, ARTHUR GvBURLEIGH, a citizen of the United States, and a resident of Sewickley, in the county of Allegheny and State of Pennsylvania, have invented a new and Improved Optical Pyrometer, of which the following is a full, clear, and exact description.

This invention relates to measuring instruments, and deals more particularly with pyrometers of the optical type especially adapted for ascertaining the color of metal at various temperatures, the instrument being especially adapted for use in heat treatment laboratories, as it can be placed adjacent the furnace and the temperature of the work therein determined by color comparisons between the work treated and indicator of the pyrometer, although the instrument is useful in classroom work, whereby an instructor in metalworking can demonstrate to the students the exact color of the heated metal at various temperatures.

The invention has for its general objects to provide an improved indicator which is heated by the passage of current ,therethrough, which can be regulated for various temperatures, wherebythe color of the heated metal can be effectively demonstrated, the indicator including means for holding a strip of metal which can be heated and reheated at high temperatureswithout changing its physical properties and without oxidizing, and in front of this strip is a shield having a small aperture directly in line with the center of the strip so as to expose the most evenly heated portion thereof, and surrounding the metal strip and shield is an inclosing cylinder of glass to protect the heated strip from air currents and at the same time allowing the. heat to escape.

For a more complete understanding of the invention, referenceis to be had to the following description and claims taken in connection with the accompanying drawing, wherein similar reference characters indicate corresponding parts mall the views, and in which- Figure l is a vertical section of the indicator, showing the same in connection with a circuit diagram; Fig. 2 is a front view' of the indicator with portions broken away;

and Fig. 3 is a horizontal section on the line 3-3, Fig; 2.

Referring to the drawing, 1 designates Specification of Letters Patent.

Patented Dec. 1, 1914.

' Application filed September 3, 1914. Serial No. 859,996.

a flat strip of any suitable metal which can i be repeatedly heated without oxidizing or changing its physical properties, and this is mounted with its ends in clamps 2 and 3, respectively, which are electrically connected with large brass terminal elements 4 and 5. The strip 1 is mounted within a. glass cylinder or equivalent housing 6 which protects the metal strip from air currents and keeps the surrounding conditions practica-lly constant, the cylinder being provided a with heads 7 and -8, of which the formed is made a part of the terminal 4. The terminal 5 extends through an opening 9 in the lower head 8, the opening being large enough to provide for ventilation. Within the casing and positioned in front of the strip 1 is a metal or other shield 10 that has. an opening 11 of about three-quarters of an inch in diameter that is directly in front of the center of the strip 1, as the center of the said strip is the more evenly heated portion thereof, and it is through this opening 11 that the strip is exposed for observation. The upper terminal 4 has an opening 12 for receiving a suitable fastening whereby the indicator 'is secured to a. panel or other support, and a bracket 13 is applied to the lower terminal, and by means of it the lower part of the indicator is fastened to a supporting panel. The lower head 8' may be supported by this lower bracket 13. The terminals 4 and 5 are provided with screws or equivalent means 14 and 15 that serve asbinding posts for connecting the indicating device in the secondary circuit of the pyrometer apparatus.

In using the indicatra transformer T is employed to step down the voltage. The secondary 8 consists of about two ampere turns and is connected by copper bars or the like indicated. by 16 and 17, with the terminals 4 and 5. For a primary supply circuit of one hundred and ten volts, the primary winding p will have about three hundred and fifty ampere turns, and the terminal of this winding is connected with the conductors 18 and 19. In the side of the circuit 18 there is an adjustable resistance 20 whereby the line voltage canbe-reduced' 'thevoltage. A rheostat 22 is employed in connection with the circuits and it has a suitable number of contacts 23 for connection with the sections of the divided resist- 811C824, and cooperating With this series of contacts 23 is a movable contact 25 whereby a the invention appertains, and While I have described the principle of operation, together with the device which I now consider to be the best embodiment theredf, I desire to have it understood that the device shown is merely illustrative and that such changes may be made when desired as are Within the scope of the appended claims.

Having thus described my invention, ll claim as newand desire to secure by- Letters Patent:

. 1. A pyrometer including an indicator, consisting of terminal elements, a metal strip fastened thereto for heatccolor indica- Y tions, an inclosing casing therefor havin .atransparent wall, and a shield provided with an'opening exposing a portion of the a said strip.

mineral 2. A pyrometer including an indicator consisting of terminal elements, a metal strip for" heat color indications,'means for clampfor connecting the strip'to a source of current, an inclosing casing, and a shield therein having an opening through which a portion of the strip is exposed.

4. A pyrometer indicator comprising a terminal piece formed with a head. a glass cylinder having one end closed by the head,

ahead for the other end of the cylinder and provided with an opening, a terminal piece extending into the opening, an element heated to different colors by current, means'tor connecting the same to the terminal pieces, and a shield Within the cylinder fastened to one of the heads, said shield having an opening for exposing the central portion of the said element. p Y

In testimony whereof l have signed my name to this specification in the presence of two subscribing Witnesses.

ARTHUR ClllLLEY BURLEIGH,

Witnesses:

CARLEToN WARREN, G; D. MORRISON. 

